Head Gasket Trimming Idea

ludwig said:
I've been doing that for ages on 850 gaskets , so that they look more like 750 gaskets .
More equal surface all around , higher specific pressure , better cooling ..
Remove white coloures area :

Head Gasket Trimming Idea
Click to expand...
 
oldmikew said:
Ludwig.. Wonder why you use composite as apposed to copper gasket?
Click to expand...
Perhaps because they work?
I don’t mean that to sound flippant!
I what I mean is that even on my 10.5:1 CR, abused, 850, the compoite head gasket has not ‘blown’.
And, unlike copper, it’s also free of oil leaks.
I’m no Norton expert, I’m quite new to Cdos and have only fitted 2 head gaskets to mine (plus the one it had when I bought it) and they have all been failure free and leak free.
BUT... that’s on standard type iron barrels (no liners or lips etc).
 
Certainly mine has always had composite gaskets and yes they work very well but possibly at a price of incremental interference with heat flow. There were two versions of the composite gasket .the plain one did tend to blow but this was revised for the metal lipped version . Whether it contributes to very slight head warping , who knows?
 
robs ss said:
Danno
Within reason, I don't think it's important to get consistency - just thinner than the areas you want clamping pressure
Click to expand...
I was referring to ADDING thickness with solder as a substitute for gluing wire to one side or the other.
 
robs ss said:
Okay - my latest thinking (thanks for the comments Slick) is...
(the drawing is a bit rough - but I think you'll get the idea)
If I'm going to etch the hatched area down from 0.036" to say 0.025" then the whole gasket will be more robust (than the trimmed/cut version).
So I won't need the "rings" around each bolt/stud hole.
Therefore the only areas needing full thickness (read full pressure) are the 5 annular rings around the bores/pushrod tunnels/oil gallery.
I've investigated the etching/masking process and looks do-able - so my latest mark-up is...
View attachment 4923
This should yield four to five times the clamping pressure at the critical areas - worth going for!
Comments welcome!
Cheers
Rob
Click to expand...
That sure LOOKS like a composite gasket.:cool:
 
Danno said:
That sure LOOKS like a composite gasket.:cool:
Click to expand...
No Danno - its copper.
Well, actually its a drawing of a copper gasket. The cross-hatched area is simply where the copper is etched to be thinner that the un-hatched (white) area.
I'm still working with old gasket material to get a reasonably even 5 - 10 thou etch.
I have a masking agent that works well but a bit more work to do on etching consistency!

I'll post a photo when (if?) I'm successful.
 
Last edited:
I follow this with interest. Triumphs and old two-strokes have gaskets that look like the trimmed examples.
 
Danno said:
I follow this with interest. Triumphs and old two-strokes have gaskets that look like the trimmed examples.
Click to expand...
Me too. I read the original article in Real Classic and thought it was a good idea. It seems it's not a new idea though, as apparently truck mechanics used to do this years ago. My personal opinion is that material should be left around the studs / bolts to stop any slight distortion. You could tin and wipe the area around the pushrod tunnels, that would give a very thin coating.

I have tried to bring this idea to a wider audience by mentioning this thread here..

https://www.accessnorton.com/NortonCommando/annealing-a-solid-copper-head-gasket-2015.19379/


No takers yet though.


Cheers,

cliffa.
 
Last edited:
Back
Top